The Depends field should also be used if the postinst, prerm or postrm scripts
require the package to be present in order to run. __Note, however, that the
postrm cannot rely on any non-essential packages to be present during the
purge phase__.

NOTE: it has not been verified that this error really caused the package to
fail the piuparts test, but it did fail.
There are also successful logs with "command not found" (though not listed below).